The economic success of stimulation treatments such as matrix acidizing often cannot be evaluated until after several months of production following clean up of the well and recovery of the injected fluid from such treatments. The initial evaluation of the engineering design must therefore be made from data obtained on site either immediately prior to the treatment, during the pumping, or immediately following shut down. Since the early 1980's, advances in monitoring stimulation treatments have included the use of microcomputers to gather digital data records.
This technology is widely used in hydraulic fracturing to calculate bottomhole treating pressures, determine formation response to the treatment and to model the growth of hydraulic fractures. Techniques to analyze pressure falloff data and pressure data obtained during the treatment have found widespread application. Despite the wide usage of matrix stimulation, a significant portion of matrix treatments fail to improve well productivity. There are several reasons for such failures, including incorrect field procedure, incorrect design or using the wrong fluid for stimulation. In particular, it appears that there are significant problems in the area of sandstone acidizing.
Current practices for selecting wells for matrix treatment are by evaluating production and water injection history, or by pressure buildup analysis. Design techniques are based on rules of thumb and past experience. Onsite monitoring and execution tools for matrix acidizing are generally based on analog pressure gauges, together with a barrel or pump stroke counter. Unlike hydraulic fracturing, real time quality control, job monitoring and job optimization is not widely practiced or available.
Thus, there exists a need for real time process control and monitoring for such jobs in order to optimize their effectiveness.